There has been known a technique of monitoring the state of a network between terminals by: copying a communication packet communicated between the terminals; sending the copied communication packet (hereinafter also referred to as “copied packet”) to an analyzer device; and analyzing the received copied packet by the analyzer device. An example of the analysis is measurement of a round trip time (hereinafter also referred to as “RTT”). For example, a mirroring function of a switch provided between terminals may be used to copy a communication packet and send the copied packet to a predetermined analyzer device.
As examples of related arts, Japanese Laid-open Patent Publication Nos. 2007-184799 and 2007-282004 are known.